<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <style>
        .c1 {
            padding: 10px; 
            border: 1px dashed #000; 
        }
        .c2 {
            padding: 20px; 
            text-align: center; 
            border: 1px solid #f00; 
    </style>
</head>
<body>
    <div class="c1">
        <div class="c2">内容</div>
    </div>
</body>
</html>